


Baby Brother

by MaggicSorceress



Series: Maggic's Undertale Human AU [25]
Category: Undertale (Video Game)
Genre: Alternate Universe - Human, Alternate Universe - Modern Setting, Family Dynamics, Family Fluff, Gen, M/M, Moving In Together, Reaper gets to meet Ink, courtesy of Geno
Language: English
Status: Completed
Published: 2020-04-03
Updated: 2020-04-03
Packaged: 2021-03-01 03:46:41
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,093
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23458801
Author URL: https://archiveofourown.org/users/MaggicSorceress/pseuds/MaggicSorceress
Summary: Geno always wanted a little brother.
Relationships: Error/Ink, Geno & Error, Geno/Reaper, Ink/Error, Reaper/Geno
Series: Maggic's Undertale Human AU [25]
Series URL: https://archiveofourown.org/series/1623928
Comments: 15
Kudos: 102





	Baby Brother

For as long as Geno could remember, he wanted a little brother. His mother, as lovely and gracious as she was, was unable to have another child. Which made sense.

Geno was always sickly. The last thing he wanted was to wish that on a younger sibling.

He was a pre-mature baby, but even that couldn’t be blamed for how terrible his immune system was. He spent the first four months of his birth in intensive care in the hospital, and pneumonia almost killed him when he was five, but he was still kicking. Even if he had to make regular hospital visits, and there were more pills in his bathroom cabinet than the average eighty-year-old.

Anyway, he had wanted a brother, but for a while it seemed like he would never get one.

Until he turned fifteen, and his mother adopted Error.

Error was…strange.

It could have been because he came from a less than proper household, disturbingly abusive from the little that his mother or Error had told him, but sometimes Error reacted…oddly.

That kid had about as many mental health issues as Geno had physical health issues.

It wasn’t easy for Geno, nor his mother, to adapt to the clusterfuck that was Error. If the younger’s haphephobia wasn’t acting up, it was the narcolepsy. If it wasn’t either of those, it was the schizophrenia or the claustrophobia. Now, those last two wouldn’t be such a problem if they didn’t rear their ugly heads at the weirdest possible times. Sometimes, even a crowded supermarket wound up being too much for his adopted brother, and he’d all but flee outside to wait for them to finish up.

For the first year and a bit, they fought often, and Geno had been afraid that he would never form a connection with his new brother, but eventually, after long nights spent talking, getting to know each other, and muffled tears into pillows, they made it work. Thank god for that, because a few months afterwards came Fresh.

As quirky as his second brother turned out to be, even if he was four years younger than him and Error, Geno found him very easy to get along with. Fresh was wacky, and strange, and at times apathetic, but he was fun and brought out a side of Error that even Geno struggled bringing to light.

So, even though his brothers took a while before they came into his life, Geno genuinely loved them like they had been with him since day one.

Now, if only Error would _answer his damn phone once in a while._

Finally, after about four missed calls, Error answered.

“What?!” Error snapped through the speakers. From where Geno sat in the passenger seat of his and Reaper’s relatively small car, he rolled his eyes and ignored his husband’s chuckles as they drove steadily down the streets.

“Nice to hear from you too, baby brother.” Geno quipped, making sure Error knew how annoyed he was at being ignored.

Error let out a heavy sigh on the other line. “Hi, Geno.”

“That’s better.” Geno said. “How are you?”

“Eh, no complaints.” Error said. Geno could practically see him shrugging. “Moving has been a pain in the ass, though.”

“Oh, right!” Geno gasped as he remembered. “I forgot you were moving in with Ink this month! How is he doing?”

“He’s alright. I’d pass him the phone but he’s still in the process of unpacking his damned art studio.” Error grumbled.

“Oh?” Geno said. “I thought you were moving into his place?”

“Yeah, so did we.” Error said, clearly irritated. “But his landlord threw the bitch-fit of the century and Ink decided to just move to my place instead.”

“Ah, I see.” Geno said, a smile tugging at his lips. “I didn’t think you’d let him have an art room just for himself though. That’s quite generous, Rory.”

“I thought you of all people would understand having to placate your boyfriend. Or has Reaper changed?”

Reaper let out a loud laugh and Geno flushed.

“Shut up, Error!” Geno complained. “I have you on speaker!”

“Hi, Error~.” Reaper sang. “How’s married life treating you?”

Error sputtered on the other line. “Ink and I aren’t married!”

“Really?” Reaper said. “How long have you guys been dating?”

“…3 years…” Error mumbled.

Reaper let out a whistle. “You gonna get on that, buddy?”

“Oh, shut up! Just because you proposed to my brother after dating him for three months doesn’t mean I’m going to do the same.” Error said.

To Geno’s pleasure, Reaper blushed. “…it was six months, not three. And what does it matter if he said no anyway?” 

“Doesn’t change the fact that you did.” Error said. “But anyway, what did you call me for Geno? Normally we just text.”

“Right,” Geno began, shifting in his seat slightly and staring out the window at the buildings they passed, “me and Reaper are in town, so we thought we’d pop by and visit a bit? I haven’t seen Ink since you were dating in high school, but if you guys still have lots of unpacking to do then don’t worry about it.”

“Nah, it’s okay.” Error said. “The only places that are still kind of a mess are Ink’s art room and the bedroom, but we’ll all be in the living room anyway.”

“You’re sure?” Geno asked. “I don’t want to give you too little time to tidy things up.”

“…do you realise who you’re talking to?” Error said. “As if I’d leave my house a mess.”

“I know, I know.” Geno said, laughing slightly. “I just wanted to let you know.”

“Yeah, it’s fine Gen.” Error said. “When are you guys gonna be here?”

“Thirty minutes or so.” Geno said.

“Alright. See you then!”

“See ya!”

~

“Hey, Kiki?” Error said, tapping on the frame of the doorway to the room that used to serve as a storage space, now Ink’s art room, and examined the room.

“Yeah, Ruru?” Ink said as he raised his head from the box he was rummaging through, wiping a hand across his forehead and brushing back the bangs of his, now bright purple, hair. “What’s up?”

“Geno and his husband are stopping by in half an hour to visit.” Error said. He was slightly impressed with how much Ink had managed to unpack in just a day, but this _was_ for art, so Error wasn’t too surprised. Ink had his desk all set up already, tablet plugged in and charging, sketchbooks piled up around it, and his worn wooden easel propped up in the corner. “I’m not sure how long they’ll be visiting, but if they’re here for dinner we’ll all just go out somewhere.”

“Really?” Ink said, his eyes lighting up. “I haven’t seen Geno since high school! And I wasn’t able to go to the wedding with you because of my finals…I still feel bad about that…”

“Eh, don’t.” Error said as he crossed the room to kneel behind Ink and wrap his arms around his waist. “Geno doesn’t hold it against you, and I doubt Reaper will since the two of you haven’t formally met yet. Besides, I gave your wedding gift to them and they loved it, so calm down.”

Ink sighed and leaned into Error’s embrace. “Alright. Thirty minutes, you said?”

“Yup, though it could be more knowing how my brother shops.” Error said, pressing a kiss to the back of Ink’s neck before standing again. “Did you want any help in here?”

“Nah, I think I’ve got it.” Ink said. “You go and finish the bedroom.”

“Alrighty!” Error said, trying to sound more excited about unpacking boxes as he left, Ink’s giggles following him into the living room.

~

Sure enough, bordering on forty minutes later, there came a knock at their front door. Error, who had finished up the bedroom, was sitting on the couch and working on a blanket he had started knitting about a month ago when there came three quick rasps on the apartment door. He dropped his knitting, wrapping the half complete blanket around the bundle of yarn, and headed for the door. When the wooden door creaked open, he had about a second to register his brother and said brother’s husband, before he was just about mowed over by a blur of red and white, also known as Geno.

“Oh, I missed you _so much!_ ” Geno said, squeezing Error with a surprising amount of strength.

“Gen,” Error gasped, trying to ignore the cracking of his rib cage, “ _can’t breathe!”_

When Geno let him go, Error took the time to look at the brother he hadn’t seen in roughly a year. Not much had changed. Geno’s hair was as blonde as it ever had been, maybe even slightly more, and hung in wispy strands over the right side of his face, barely obscuring the eye patch that covered his right eye. His left eye was the same blue as it had always been, and he wore the same red scarf that Error had knitted for him for his seventeenth birthday. Geno looked at him as well for a moment before he frowned.

“When did you get taller than me?” Geno grouched.

“I’ve always been taller than you.” Error said as he moved around his brother to give Reaper a quick half hug, avoiding a small white box the other was carrying. Reaper, dressed in a dark hoodie and equally dark jeans, gave Error a smile.

“How’s it going?” Reaper said.

“Eh.” Error said. As they moved away from the doorway, Ink came scampering out of his art room, brushing his hands off of his overalls and running his hands through his hair in a vain attempt to tame it. He smiled at Geno and the two of them embraced, Ink bouncing on his heels.

“It’s so good to see you!” Ink practically squealed. “I’m so sorry I couldn’t come to the wedding but-“

“Don’t you worry about it!” Geno said. “Error gave us your gift and the painting is _so beautiful, Ink!_ ”

Ink pulled out of the hug and smiled bashfully. “Aw, it was nothing; I had fun making it.” Geno smiled, glancing between Ink and Reaper and pausing to give Error a pointed look. It took Error longer than he wanted to admit to realise what his brother was trying to indicate.

“Oh, uhm,” Error began, clearing his throat, “Reaper, this is Ink. Ink, this is Reaper.”

Reaper walked over to Ink and held out a hand. Ink shook it, trying to fight the shudder that went up his spine at how cold Reaper’s hand was. The other’s smile was kind though, and his dark eyes held a gentleness that made his rather dark demeanour much softer.

“It’s nice to finally meet you.” Reaper said. “I’ve heard a lot about you.”

“Same here.” Ink said. “Congratulations, by the way.”

“Thank you.” Reaper said, voice soft. He held up the box he had been holding and gave it a slight shake. “This is your unofficial moving in celebration though, so Geno suggested we pick up a cake.”

Geno glanced at his brother and Ink. “It’s chocolate. Is that okay, Ink?”

“Are you kidding?” Ink laughed. “If I didn’t like chocolate, he’d never agree to let me move in.”

“You’re damn right.” Error said.

Ink laughed again, before something seemed to catch his attention and he gasped, reaching over to grab Geno’s hands. “Your engagement ring! Lemme see!”

Geno giggled, but extended his left hand for Ink to admire. It was a simple ring, but just elegant enough to meet Reaper’s incredibly high standards for what was good enough for Geno. Error frowned, a sigh he didn’t know he was holding in passing through his lips, and Reaper glanced at him.

“So…” Error mumbled, quiet enough to not be heard by the two other’s present in the house but loud enough for Reaper to hear, “where did…uhm…you get it?”

The corner of Reaper’s mouth quirked upward. “That place downtown. Had to get it adjusted twice, Geno’s fingers are strangely shaped. Not that I’m complaining.”

“Well, we can’t all have your piano fingers.” Error said with a small smile. “…and thanks.”

“No problem.” Reaper said. “Just…don’t stress out about it.”

“Like you did?”

Reaper winced. “Well…yeah. But, I mean it.”

“…gotcha…” Error mumbled, eyes downcast.

“Well!” Geno said, gaining everyone’s attention. “We can all catch up over cake! Error, help me find your plates.”

Error sighed and followed his brother into his kitchen. “Sir, yes sir.”

**Author's Note:**

> All this was, was setting up Geno and Error's relationship  
> Regardless, I hope you all liked it! Comments and kudos are greatly appreciated! <3  
> -Maggic


End file.
